This invention relates to a steer knuckle for a heavy duty vehicle, and more particularly, the invention relates to a steer knuckle suitable for a front drive steer axle having drum brakes.
Heavy duty vehicles commonly include multiple drive axle assemblies. The drive axle assemblies are steerable, or permit the wheel ends to rotate relative to an axle housing during a vehicle turn, to provide better maneuverability of the heavy duty vehicle. Furthermore, the axle assemblies typically incorporate brake drums for providing a robust braking design and suitable stoppability for a heavy duty vehicle. Steer knuckles are supported on either end of the axle assembly for rotation by king pins. A wheel end assembly is supported on the knuckles and houses the brake shoes. Brake components such as an air chamber, rod, brake adjuster, and brake cam must be supported on the steer knuckle to pivot with the steer knuckle and wheel end assembly. As a result, the location and packaging of the brake components relative to the axle housing often dictates the amount of rotation of the knuckle that is permitted relative to the axle housing, or the turn angle.
In the prior art, a multi-piece bracket is bolted on a portion of the steer knuckle to support a end of the cam shaft. The cam bracket typically includes a pair of stamped metal bracket portions that support a bearing and are fastened to one another by numerous bolts. The cam bracket is then fastened to he steer knuckle with several fasteners. The multi-piece cam bracket is costly because it includes many components and is rather bulky. As a result, for some steer axle designs, the cam bracket prevents the knuckle from steering or pivoting an acceptable amount, or having an sufficient turn angle. Therefore, what is needed is an improved cam support for supporting an end of the cam shaft to permit an acceptable turn angle.
The present invention provides a steer axle for a heavy duty vehicle including an axle assembly having an axle housing. A steer knuckle is connected to an end portion of the axle housing by king pins. The steer knuckle rotates relative to the axle housing about the king pins. A wheel end assembly including a brake drum and a pair of brake shoes is supported on an outer wall of the steer knuckle. Preferably, one end of a cam shaft is supported by the wheel end assembly, such as by a spindle. According to the present invention, the steer knuckle includes a boss extending from a portion of the steer knuckle. The boss has a hole, and preferably, a bushing is received in the hole to support the other end of the cam shaft. Other brake components such as an air chamber, rod, and a brake adjuster are supported by the knuckle and connected to the cam shaft to rotate the cam shaft about its axis and force the brake shoes away from one another with a cam and into engagement with the brake drum.
Accordingly, the above invention provides a steer knuckle for supporting an end of the cam shaft to provide a more compact design and provide a greater turn angle.